Analysis of local vs. macroscopic properties of porous BaTiO3 ceramics based on 3D reconstructed ceramic microstructures

In the present work, ferroelectric BaTiO ₃ ceramics with variable porosity level (96%, 89%, 81%, and 74% relative densities) and anisotropy derived from the deformation of sacrificial soft polymeric additives during the pressing step, are investigated by an experimental-numerical approach. 3D micro X-ray computed tomography experimental data with specific numerical procedures are firstly used to reconstruct the 3D microstructures of the porous ceramics and to extract geometrical information concerning the samples. These 3D microstructures are then employed as input in FEM models, in order to determine the local electric field and potential distributions inside the ceramic, with the final aim of evaluating low field effective dielectric permittivity and high field ferroelectric switching P(E) features as a function of porosity and field direction. The dielectric and ferroelectric properties derived by using this procedure are discussed in comparison with experimentally determined ones. The paper demonstrates the usefulness of analyzes and simulations of properties at different lenghtscales based on real 3D microstructures, in such ceramic systems, in completing the understanding of the complex relationship between composition – microstructure – local/macroscopic properties.